West Bank Running Rich ???

[Stangly]

This strange code keeps popping up on my scanner (west bank running rich). This is on a 02 XLT 4x4 4.0 6 w/82,000 mi. She's running great, but must get that light OUT. OK, strange because - all filters are fresh(air/fuel), plugs are fresh, fuel pressure is normal, TPS & MAF sensors show proper voltage, timing is dead on, YET I'm told by a 'Ford Tech' to "give it a tune-up", I cannot find an answer to this code anywhere. Unfortunately, no matter how well she's running, she won't pass an emissions inspection with a check engine light on (I'm good for another 7 months, but, like they say - "Homey don't play that"). Anyway, new O2 sensors are next with crossed fingers. If anyone has ever come across this code, any 411 would be greatly appreciated.

 

[steventadams]

What's the actual code number? Usually when a code points to an O2 sensor it means there is something else run further upstream...

 

[Stangly]

I'll re-run tomorrow and grab the actual number. But that's the thing, I get a # and 'west bank running rich'. No sensor, no nothing - that's it. Weird.?. Next post will be straight from scanner..........Thanx

 

[E.B. Cornburner]

Could be an injector leaking down. If you have a fuel pressure tester, do a key-on-engine-off fuel pressure test, then see what sort of leakdown you have. I wouldn't want to see more than a 10 PSI loss in about half an hour or so.

Your long and short fuel trims should give you an indication of this too. At normal operating temp in closed loop, the LTFT should be close to 0... +/- 5% max.

Look at your forward O2 sensor activity too. B1S1 and B2S1 should be showing some nice crosscounts, not hanging overly rich (over 450mV) or lean (under 450mV), but should dance around quickly, passing over and under that 450mV center point nicely.
It could be as simple as a sluggish O2 sensor, though I rarely see them hanging rich...Usually they're hanging lean if they're getting tired.

 

[Stangly]

Actual Code

Sorry, my scanner grew some legs and had to be tracked down (ughh). This is the actual code: P0175 System Too Rich (Bank 2).